The present invention relates to elongated decorative mouldings, for protecting the bodies of land and water vehicles and the like from damage caused by minor impacts. In particular, the invention relates to mouldings of this type which comprise an extruded strip having a decorative strip attached thereto and carrying adhesive means for fastening the moulding to a vehicle body.
Such mouldings have enjoyed increasing popularity since about 1965 among auto body customizers and the automobile-buying public. The growth in popularity of these mouldings was not only because of their decorative qualities but also because they significantly lessen the paint chipping and minor dents inflicted in parking lots by the careless opening of adjacent car doors. More recently, automobile manufacturers such as the Ford Motor Company have been installing such mouldings on their new vehicles for the above reasons and because they did not require fasteners as did the chromed metallic moulding strips which had previously been used on new cars.
In their most popular form, such mouldings are formed by laminating a decorative strip of thin material (for example vinyl or polyvinyl chloride material) to the impact-absorbing surface of a thicker extruded strip of, for example, vinyl or polyvinyl chloride material. The exposed outer surface is typically coated with a metallic material such as aluminum in order to present an attractive chrome-like appearance to the decorative strip. Because the metallic material is susceptible to discolouration due to weathering, it is common to use decorative strips which have a protective polyester film applied over the metallized surface.
In practice, such decorative strips are formed by first metallizing a wide, thin sheet of, for example, polyvinyl chloride material, laminating it with a wide polyester film, and then slitting the metallized, polyester film covered sheet into narrow decorative strips. Unfortunately, slitting causes slight delamination of the polyester film from the metallized surface along the edges of the decorative strips. This "slitting delamination" later permits weathering and discolouration of the metallic decorative material after the decorative strip has been attached to the thick extruded strip to form the finished moulding and the later has been attached by a adhesive to a car body. It is believed that this discolouration is caused by the progressive action oxidation, salt and other corrosive elements of the atmosphere which begin at the edges of the decorative strip and gradually corrode most of the aluminum or other metallic material between the polyester film and the polyvinyl chloride strip. As a result, the decorative strip typically becomes dull and discoloured within about one year after the moulding has been applied to the vehicle body. Such discolouration is very undesirable and gives rise to numerous consumer complaints.
Previous attempts at overcoming this problem have met with little success. The most common approach has been to bury the edges of the decorative strip into the thick extruded strip in order to prevent their exposure to weathering. Unfortunately, this solution is complex, is unsuited to many popular decorative moulding designs, and may even cause delamination of the protective polyester film by the migration of plasticizer compounds from the thick extruded strip into the adhesive used to attach the polyester film over the metallized decorative strip.
Accordingly, it is the principal object of the invention to provide an elongated decorative moulding which is highly resistant to weathering and the attendant discolouration of the metallized or otherwise decorative strips carried by the moulding.
It is a further object to provide a weather-resistant moulding which obviates the need to use expensive decorative strips which have a highly weather-resistant polyester film laminated thereto.
It is a further object to render the moulding weather resistant while permitting production thereof to be carried out with safety at the extrusion rate of the thick extruded strip.